I wanted as light as possible, so instead of locking arms,
I made something to prevent the nut from turning.
I bought a metal nibbling tool
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=97636I took a chunk of scrap aluminum and drilled, then cut a hole the
size of the 15/16 nut. Then I cut out the scrap with room for
a screw hole. Once I had the nuts torqued, I marked and drilled
a hole through the fender screw hole in the fork.
I drilled several holes so that I could line up the screws if the nut
were in a different position.
I repeated the process for the wired side, but cut an extra slot for the wires
to go through.
Now the nuts just can't come loose.